Disc type electron tube with improved cathode, grid, and anode elements



Sept. 13, 1955 w. WIHTOL 2,717,974

DISC TYPE ELECTRON TUBE WITH IMPROVED CATHODE, GRID AND ANODE ELEMENTS Filed April 8, 1952 2 Sheets-Sheet 1 33 y 39 4 38 5 as 35 37 [H /e o f 5 I l7 l4 q /3 l0 z' I I 23 LIZ 22 1- 5 [9 z J/J 2/ I I. b: 30 I -32 20 q? ze- 24 INVENTOR. 25 a, 9 WEL r/s W/HTOL BY 1' W TM ATTORNEYS Sept. 13, 1955 w. WIHTOL DISC TYPE ELECTRON TUBE WITH IMPROVED CATHODE GRID AND ANODE ELEMENTS 2 Sheets-Sheet 2 Filed April 8, 1952 INVENTOR. WEL 7/8 W/HTOL AT TORNE Y5 United States Fatent Ofifice Z ,7 1 7 ,9 74 Patented Sept. 13,-. 1955 DISC TYPE ELECTRON TUBE WITH IMPROVED CATHODE, GRID, ANDANGDE ELEMENTS Weltis-Wihtol, Chicago, Ill.

Application April. 8, 1952; Seri'alNo. 281,107

3Claims; (Cl; 313-293) This invention: relates to an electron tube particularly adaptedifor'ultra-highefrequency operation and more specifically to an improved disc type electron tube with improved cathode, grid and anode elements.

It is an; object of this invention to provide a disc or lighthouse type tube in: whichthe transit time is reduced below that found in. presently existing lighthouse or disc type tubes.

It is. a further object: of this invention to provide a sturdy grid construction which. provides for positive grid control. at reduced grid current and with rapid heat dissipation whereby less grid; driving power is required than in: other tubes and whereby the. grid emission problems are lessened.

It is an. additional object of. this invention to' provide at tube-in which the spacing of the: elements has a much greater available range of spacing. than. that. heretofore experienced.

It is still another objectv of: this invention to provide a disc type tube: in. which the adjustability of the anode spacingzwith respect to: the-other elements may be accomplishedpractically;

These and other objects of the invention will appear from the following description in connection with the accompanying drawingswhich illustrate one embodiment of the invention and in which Fig. l is an axial sectional view of an electron tube embodying. the invention;

FigfZl is an axial partial sectional view of the electron tube illustrated inFig. l substantially on the line- 22 ofFig; 1;

Fig. 3 is a plan View of the control grid used in the electron tube illustrated in Fig. 1;

Fig. 4 is a detailed cross sectional view substantially on the line 4-4 of Fig. 3;

Fig. 5 is a plan view of the cathode used in the electron tube illustrated in Fig. 1; and

Fig. 6 is a detailed cross sectional view substantially on the line 6-6 of Fig. 5.

The invention is illustrated in connection with an electron tube of the type generally known in the art as either the disc type tube or the lighthouse tube. Such tubes are well known and examples appear in such patents as the Donald F. Drieschman Patent No. 2,446,269, patented August 3, 1948, and the Donald F. Drieschman et al. Patent No. 2,458,693, patented January 11, 1949.

Such tubes are disclosed in said Patent No. 2,458,693 in the form of a triode structure comprising an anode 10, grid 11 and cathode 12 arranged with active surfaces disposed in parallel planes. These electrodes are mounted in a suitable envelope comprising a body section 13 of vitreous material, such as glass, sealed at one end to an anode supporting member 14 and at the other end to a tubular envelope section 15. The anode supporting member 14 also functions as the anode terminal and comprises a metal cup having a cylindrical Wall 16 extending from a flange 17 to which the glass is sealed.

Tubular envelope section is a cylindrical shaped metallic member having an? outwardly turnedflange 18 to which the glass body'section: 13- is. sealed. Section 15 is arranged coaxially with anode supporting member 14 and: itfunctions also as. the terminal for grid 11.

Grid. 11' is supported upon an inverted cup-shaped member 19 provided with a cylindrical portion 20' which contacts the interior surface of the tubular envelope section 15. The upper end of the cylindrical portion 20 is provided with an inwardly extending flange 21 and the latter is provided with an upwardly extending cylindrical portion 22. The grid 11- is secured to an inwardly extending flange 23 extending inwardly from .the top of the cylindrical portion 22.

The cathode 12 is mounted on a stem24 arranged co axially with the envelope so as to project into the'envelope through tubular envelope section 15. The cathode stem 24 comprises a pair of concentric stern. members including an. outer tubular part 25 and an inner rod-like part 26. These stem members are joined together by a glass seal. 27 between the rod 26 and the tubular part 25. The stem 24 in turn issecured to the tubular envelope section 15 by aglass seal- 28 between the lower end of the envelope section 15 and the stem 24. A cup-shape terminal 29 is affixed to the outer end of rod 26.

The cathode 12 is supported upon an inverted cylindrical cup 30 which is coaxial with, and which is secured to, the inner end of. the outer tubular part 25. The cathode heater 31 comprises a spiral filament 31 having one end connected to. the rod 26 by bracket 32 and the other end connected to the inverted cylindrical cup 30. A cylindrical baifle 33' is arranged between the cathode heater 31 and the'cylindrical1cup 30 to confine the: heat and direct it upwardly toward the cathode 12.

The structure, described above, is in general quite Well known in the art and is recited merely to describe the preferred environment. for this invention. The invention itself has autility in connection with this environment and it comprises the combination of elements hereinafter to be described. The particular attention of the reader is. directed to the claims appended to this specification.

The anode 10. of the applicants improved electron tube ispreferably of metal having, good heat conductivity, such as copper, with a fl'at' anode surface presented interiorly of the envelope. The anode 10 has a stem portion. 34 extending outwardly from the interior ofthe envelope. The reduced stem portion 34 of the anode and the anode are arranged for axial movement in the manner to be hereinafter described.

The anode supporting member 14 carries a collar 35. This collar 35 is provided with a cylindrical outer surface 36 and with a cylindrical bore 37. To this collar 35 there is secured a washer 38. The washer 38 is provided with a cylindrical bore 39 which embraces the reduced stem 34 of the anode with a sliding fit. Arranged outwardly of the washer 38, there is provided a suitable cooler 40 carrying a series of transverse disc-like cooling fins 41. The cooler 40 is provided with a cylindrical bore 42 which embraces the reduced stem 34 of the anode with a sliding fit. A washer 43 overlies the cooler 40 and a micrometer adjusting screw 44 overlies the washer 43.

The micrometer adjusting screw comprises a thimble 45, a sleeve 46 and a movable spindle 47. The usual micrometric calibrations are placed upon the thimble 45 and the sleeve 46. The sleeve 46 is secured to the washer 43 and the spindle 47 is secured to the reduced stem 34 of the anode.

The assembly comprising the collar 35, the washer 38, the cooler 40 and the washer 43 is secured by means of two screws 48 which extend through the washer 43, the cooler 40 and the washer 38 and which are threaded into the collar 35. The washer 43 is spaced from the cooler 40 by means of washers 49.

A vacuum tight bellows 60 inter-connects the collar 35 with the anode 10 and serves both as a conducting means between the anode 10 and the collar 35 and as a vacuum retaining means to prevent breaking of the vacuum.

The tube is exhausted through a metal tubulation 51 which extends through the plate 43, the cooler 40, the washer 38 and the collar 35 into the interior of the electron tube. After exhausting the tube, the tube is sealed by means of a glass tubulation 52 by pinching off the tubulation at the tip 53.

The grid 11 of the preferred embodiment of this invention comprises a dish-shaped metal plate having a depressed portion 54 and a raised rim 55. Seven round openings 56 are provided in the depressed portion 54 of the grid 11. The raised rim 55 of the grid 11 is secured to the inwardly extending flange 23 of the inverted cupshaped member 19.

The cathode 12 comprises a disc provided with seven upraised projections 58. The projections 53 have a diameter slightly less than the diameter of the openings 56 and the projections 58 are placed so as to register with the openings 56. The disc 57 is secured to a flat plate 59 which in turn is secured to the upper end of the cylindrical cup 30. In assembly care should be taken that the projections 58 are in axial alignment with the openings 56.

It will be observed that the side wall 60 of each projection 58 has a diameter smaller than the diameter of its companion opening 56. This permits a telescopic nesting of the cathode and grid should that arrangement prove to be desirable for the particular purpose for which the tube is to be used.

It will be observed that the foregoing structure produces a tube of great mechanical strength in which the transit time between the cathode and the anode is reduced to a minimum. Although reducing the transit time, this improved structure still retains proper grid control. It will also be observed that the grid current requirements are low thus requiring relatively low driving power in oscillator and amplifier uses. Moreover, the grid dissipates heat far better than usual grids. This permits the grid to operate at a lower temperature, thereby reducing grid emission problems. cathode grid and adjustable anode is such as to produce for the first time a truly practical tube with adjustable spacing of the elements.

It is to be understood that this invention is not limited Finally, the combination of to the specific embodiment disclosed herein but is capable of modifications falling within the scope of the appended claims. Having thus described a selected embodiment of this invention, the invention itself is claimed as follows.

I claim:

1. In an ultra high frequency high vacuum tube having a low electron transit time, a cathode having a plurality of integral projections and a closely adjacent grid having a plurality of perforations, the perforations in said grid coinciding in number, shape and dispersal with the projections on said cathode, the dimensions of said perforations being slightly larger than the dimensions of said projections whereby the relative placement of the cathode and grid with respect to each other may be varied over wide range including a telescopic relation between said projections and said perforations.

2. In a high vacuum tube having a low electron transit time, a closely adjacent grid having a plurality of perforations and a cathode having a plurality of integral projections, the projections on said cathode coinciding in number, shape and dispersal with the perforations in said grid, said cathode projections extending a distance of the order of the transverse dimension of said cooperating grid, the dimensions of said projections being slightly less than the dimensions of said grid perforations whereby the distance between the cathode and grid may be so small that if the one surface of the grid adjacent the cathode were extended it would intersect said cathode projections.

3. In an ultra high frequency electron vacuum tube having a low electron transit time, a sheet metal cathode having a plurality of integrally formed projections each of circular configuration, and a grid closely adjacent to said cathode and having a plurality of perforations coinciding in number, shape and dispersal with the projections on said cathode, the diameter of said perforations being slightly larger than the diameter of said projections whereby the axial placement of the cathode and grid with respect to one another may be varied over a wide range to a distance so small that if one surface of the grid adjacent the cathode were extended it would intersect said cathode projections.

References Cited in the file of this patent UNITED STATES PATENTS 2,130,281 Knoll Sept. 13, 1938 2,207,846 Wolff July 16, 1940 2,416,318 Hotine Feb. 24, 1947 2,443,535 Haas June 15, 1948 2,605,439 Boyer et al July 29, 1952 

